From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article discussing the engineering and economic possibilities of lowered wind resistance in automobiles.
| Identifier | ExFiles\Box 161\1\ scan0076 | |
| Date | 25th January 1938 | |
| JANUARY 25, 1938. 1143 The Motor The Engineering and Economic Possibilities of Lowered Wind Resistance: the Influence of Road Conditions and a Discussion of Some Problems By Laurence Pomeroy, Junr. At 70 m.p.h. the streamlined job, of course, still has advantages, but this is a speed within the compass of the normally sized engine in a normal car, and there is no doubt that the conventional form has advantages from many points of view. Position of British Designers Provided, therefore, a 70 m.p.h. maximum is accepted on account of road conditions, there is little incentive for British manufacturers to undertake experimental work on streamlining. If and when we have English roads on which sustained high speeds are possible, there is no doubt that the skill that has won supremacy for England in the aircraft field will be an invaluable aid to the British automobile manufacturer. The gains that would accrue from such a system of roads and cars capable of making full use of them are substantial. Not only are there many advantages in respect of the direct saving in time that would result, but there are even more important considerations from the viewpoint of personal and national economics. This can be seen well by taking the case of three business executives who are undertaking a 180-mile journey. Supposing they are individually worth to the company employing them a matter of 10s. an hour, the loss to the company during their transport time is a matter of some 30s. per hour. If, therefore, they take a 180-mile journey on a car doing 30 m.p.g. at an average of 30 m.p.h. their costs work out as follow:— Fuel, six gallons, 9s. 6d.; cost of idle time at 30s. per hour for six hours, 180s.; total, £9 9s. 6d. If they travel as an alternative by train their costs will be roughly as follow:— Fares, £3 16s.; idle time three hours on train, plus, say, half-hour to and from stations, £5 5s.; total, £9 1s. Compared with either of the above alternatives the economics of the high-speed automobile are staggering by the savings which are shown. Suppose that of 180 miles 20 miles is covered at an average speed of 40 m.p.h. (getting in and out of the terminal towns) and that an average speed of 80 m.p.h. could be realized for the remaining 160 miles, the total average speed would amount to 72 m.p.h., and the idle time for occupants for 2½ hours, 75s.; fuel at 20 m.p.g., 15s.; total, £4 10s. If one adds the liberal figure of 3d. a mile for depreciation and maintenance charges on the high-speed car, involving an additional cost of £2 5s., one has a total of £6 15s., whereas assuming that the slow car has a lower depreciation and maintenance cost of 2d. per mile, its total will be £11 9s. It will thus be seen that, despite a good fuel consumption, the slow car is fundamentally a hopelessly uneconomic form of transport. The fast car, on the other hand, if given a suitable system of highways, can actually beat the train by nearly 30 per cent. in door-to-door time and by 25 per cent. in cost. It follows that if we in England neglect to provide such highways at a time when they are available to Continental business men, we are to that extent handicapping the business of the country. Road Safety and Economics There is, therefore, a strong economic reason for the building of such roads, apart altogether from the overwhelming case that can be presented for them from the viewpoints of safety and reduction in physical and mental wear and tear. In Germany, where such roads are being constructed at the rate of some 600 miles per annum, many manufacturers are experimenting with the streamlined car. It must not be thought that it is impossible to obtain any real gains from streamlining unless radical chassis alterations are made. If such were the case almost the entire benefits of the theory will be lost. There can never be more than a MODERATO. At 70 m.p.h. the normal car needs 50 h.p., of which about 38 is absorbed by wind resistance. The streamlined car, therefore, shows to increased advantage, as will be seen by contrasting the engine areas representing horse-power in this drawing. (Diagram labels: M.{Mr Moon / Mr Moore} P. 70 H.{Arthur M. Hanbury - Head Complaints}) CRESCENDO. At 90 m.p.h. the normal car needs 120 h.p., of which 100 are spent in overcoming wind resistance. At this speed, therefore, the streamlined car shows to very great advantage, the relative horse-power being more shown by the two shaded areas. (Diagram labels: 90, A25) | ||